This invention relates to a high-quality character generating system which generates visible high-quality characters, symbols, and the like from coded digital character data, for example, in a laser printer, a CRT disk player, and a phototypographic composing machine with an electronic computer.
Digital character generating approaches include the dot process and the vector process approaches. The dot process approach generates characters readily, because the characters are stored beforehand in a memory as the same dot data as are used for displaying the characters. On the other hand, the dot process requires extremely large memory capacity, because spaces must be stored in coded form, as well as the picture elements of characters. As a result, a larger amount of data is required for one character: Also, the dot process needs separate character data for different sizes of characters, even for different sizes of the same character.
In contrast to this, the vector process approach can work with a smaller capacity memory because it stores only the segments of lines in characters as vector data in the memory. As a result, the vector process is capable of displaying characters through free variation of the prescribed value to produce desired sizes of characters, even only if one set of character data is stored in the memory.
Moreover, this vector process includes the stroke process and the outline (polygon) process. The stroke process, which is composed of a small amount of data, can display characters at high speed, but has difficulty in expressing minute and delicate changes in character type styles. In contrast, the outline process, which works with contours of characters converted to data, is capable of expressing finer details of type styles, even though it is slightly slower compared with the stroke process.
In FIG. 2, which illustrates a conventional principle used for the display of the letter A by the outline process, the contour of the letter A is expressed by segments of a line connecting the peak points a through l on the memory forming the bit map. Then, this bit map is scanned, for example, in the direction of the x axis, and the position for drawing the image (to be painted out is detected. Subsequently, this detected position (the area inside the contour line) is painted out (filled).
Thus, conventional systems are designed to operate with software so that the contour of a character is drawn on the bit map, and then the bit map is scanned and the area inside the contour is painted out. Therefore, the existing process takes a relatively long time to display a character.